Would Germany have followed a different course under Prince Heinrich?
Short answerProbably; his better understanding of Britain and weaker alignment with Tirpitz could have produced a more Bismarckian strategy and a very different European war.
NotesPrince Heinrich appears here as both a capable admiral and a comparatively decent political figure. Unlike Wilhelm II, Heinrich understood Britain and might have tried to keep it neutral or friendly while Germany pursued its interests on the continent. He was less aligned with Alfred von Tirpitz and more likely to follow Otto von Bismarck's diplomatic logic. Those differences make a First World War without British opposition, or a very different European conflict, a plausible counterfactual rather than a simple change of personality.